1. Field of the Invention
The present invention relates to an IC transportation mechanism provided with a plurality of suction units. The suction units transport ICs from a supply stage to a measuring portion and from the measuring portion to a storage stage. A device which employs such an IC transportation mechanism is, for example, an autohandler.
2. Description of the Related Art
A construction of an IC transportation mechanism of prior art will be described hereinafter with reference to FIG. 14. In FIG. 14, denoted at 5 is a measuring portion, 5A and 5B are IC sockets, 10 are ICs, 11 is a supply stage, 12 is a storage stage, 16 is a transportation mechanism, 16A and 16B are suction units and 16C and 16D are suction pads.
In FIG. 14, the supply stage 11 is arranged on a first column Y1 and shifts in the direction of the y-axis. The supply stage 11 comprises recesses 11A and 11B which are arranged on different rows. The ICs 10 are corrected in posture when they are placed on the recesses 11A and 11B. The storage stage 12 is arranged on a second column Y2 and shifts in the direction of the y-axis. The storage stage 12 comprises recesses 12A and 12B which are arranged on different rows. The ICs 10 are corrected in posture when they are placed on the recesses 12A and 12B.
In FIG. 14, the recesses 11A and 11B are the same in shape as the recesses 12A and 12B, each being a rectangular recess slightly larger than the external form of each IC 10. Since each recess is inclined at the entrance portion thereof, each IC 10 is guided by the inclined walls of each recess to be corrected in posture. The accurate positioning of the ICs 10 facilitates positioning the same relative to IC sockets 5A and 5B, described later, when the ICs 10 are transported to the IC sockets 5A and 5B from the supply stage 11, or facilitates transporting the ICs 10 from the storage stage 12 to next process.
The measuring portion 5 comprises the IC sockets 5A and 5B which are arranged on a column YM equidistant from the first column Y1 and the second column Y2. The row interval between the IC sockets 5A and 5B are the same as that between the recesses 12A and 12B.
The transportation mechanism 16 comprises the suction units 16A and 16B and the suction pads 16C and 16D. Each of the suction units 16A and 16B comprises therein a suction pad for retaining the upper surface of each IC 10 by negative pressure and a presser member to be brought into contact with the leads of the IC 10 is attached to each suction pad around the same. When the suction units 16A and 16B with the ICs 10 retained thereby by suction are pressed on the IC sockets 5A and 5B, the aforementioned presser bodies press the leads of the ICs 10 on the contacts of the IC sockets 5A and 5B. The suction pads 16C and 16D are the same as those provided inside the suction units 16A and 16B.
In FIG. 14, The suction units 16A and 16B and the suction pads 16C and 16D move vertically in the direction of the z-axis. The column interval between the suction pads 16C and 16D and the suction pads 16C and 16D is the same as that between the first column Y1 and column YM and the row interval between the suction units 16A and 16B or that between the suction pads 16C and 16D is the same as that between the IC sockets 5A and 5B. The transportation mechanism 16 moves the suction units 16A and 16B and the suction pads 16C and 16D together as one body in the direction of the x-axis.
The operation of the transportation mechanism illustrated in FIG. 14 will be described hereinafter with reference to FIGS. 15 to 17 showing the varying states thereof. FIGS. 15 to 17 are front views of the transportation mechanism in FIG. 14. In FIG. 14, denoted at 60 is a moving block, to which cylinders 16E and 16F are fixed. When the cylinder 16E is actuated, the suction units 16A and 16B move vertically being guided by a linear guide mounted on a side wall of the moving block 60. When the cylinder 16F is actuated, the suction pads 16C and 16D move vertically being guided by the other linear guide mounted on the other side wall of the moving block 60. A motor 60A is connected to a ball screw, which engages with a ball nut fixed to the moving block 60. When the motor 60A rotates, it moves the moving block 60 in the direction of the x-axis.
In a state illustrated in FIG. 15 (a), ICs 10 have been transported to the IC sockets 5A and 5B by the suction units 16A and 16B and next ICs 10 stand by on the supply stage 11. Incidentally, the measurement of the ICs 10 on the IC sockets 5A and 5B has been completed.
From the state in FIG. 15 (a), the moving block 60 moves to the side of the supply stage 11 to be in a state illustrated in FIG. 15 (b), wherein the suction units 16A and 16B are located above the supply stage 11 and the suction pads 16C and 16D are located above the IC sockets 5A and 5B.
From the state in FIG. 15 (b), the suction units 16A and 16B and the suction pads 16C and 16D descend so as to be in a state illustrated in FIG. 16 (a), wherein the suction units 16A and 16B retain ICs 10 on the IC sockets 5A and 5B by suction while the suction pads 16C and 16D retain ICs 10 on the IC sockets 5A and 5B by suction. From the state in FIG. 16 (a), the suction units 16A and 16B and the suction pads 16C and 16D ascend each with an IC 10 retained thereby so as to be in a state illustrated in FIG. 16 (b).
From the state in FIG. 16 (b), the moving block 60 moves to the side of the storage stage 12 so as to be in a state illustrated in FIG. 17 (a), wherein the suction units 16A and 16B are located above the IC sockets 5A and 5B, while the suction pads 16C and 16D are located above the storage stage 12.
From the state in FIG. 17 (a), the suction units 16A and 16B and the suction pads 16C and 16D descend so as to be in a state illustrated in FIG. 17 (b), wherein the suction units 16A and 16B press ICs 10 on the IC sockets 5A and 5B while the suction pads 16C and 16D release ICs 10 onto the recesses 12A and 12B on the storage stage 12.
From the state in FIG. 17 (b), when the ICs 10 on the storage stage 12 are transported to next process and next ICs 10 are supplied to the supply stage 11 upon completion of measuring the ICs 10 on the IC sockets 5A and 5B, the IC transportation mechanism returns to the state in FIG. 15 (a) so as to complete a series of transportation cycle.
It is difficult for the IC transportation mechanism having construction illustrated in FIG. 14 to shorten in time the series of transportation cycle since it requires time between the state in FIG. 15 (a) and that in FIG. 15 (b) and between that in FIG. 16 (b) and that in FIG. 17 (a). That is, the moving block 60 reciprocates between the supply stage 11 and the measuring portion 5 to supply the ICs 10 onto the IC sockets 5A and 5B and between the measuring portion 5 and the storage stage 12 as well to take out the ICs 10 from the IC sockets 5A and 5B, including wasteful processes.